Researchers at the Perimeter Institute for Theoretical Physics have published findings in the Journal of Cosmology and Astroparticle Physics examining theoretical models in which dark matter particles interact through a long-range force in addition to gravitational attraction. The investigation was motivated by recent high-precision observations of the Universe that have revealed discrepancies with predictions from standard cosmological models.
Observations of cosmic expansion and galaxy development have produced results that do not align perfectly with existing theories. Some measurements of the distant Universe suggest expansion proceeded more slowly in the past than expected, while studies of the cosmic microwave background indicate matter may be more tightly clustered at the largest scales than predicted. Though these differences are relatively modest, they have led scientists to consider whether the standard cosmological model may lack a crucial component.
The research team investigated how dark matter would behave if particles experienced an additional attractive force that ordinary matter could not detect. Using theoretical calculations alongside observational data, scientists modeled how this hidden interaction would influence cosmic expansion history and large-scale structure formation. Counterintuitively, while the extra force does cause dark matter to cluster more efficiently, the same process causes dark matter particles to effectively lose mass over time. This mass reduction weakens their gravitational influence, offsetting the stronger attraction from the hidden force and ultimately suppressing rather than enhancing cosmic structure growth.
The findings have implications for theories attempting to explain recent measurements from the Dark Energy Spectroscopic Instrument and could affect how scientists approach more complex models involving dark matter interactions. According to the research team, any theory proposing hidden attractive forces may need to account for dark matter becoming effectively lighter as the Universe evolves. The researchers note that upcoming observatories and cosmic surveys could help determine which hidden interactions dark matter possesses and rule out certain possibilities.
Article Attribution | Read More at Article Source
Article summary produced by Claude AI